The present invention relates broadly to devices for assisting injured or physically impaired persons to walk or move about. More particularly, the present invention relates to an automated lift device for assisting a partially ambulatory individual to rise from a chair, bed, or other support and to maneuver about without assistance from others.
Many physically disabled individuals cannot support their full body weight with their legs. However, mechanical devices may assist the injured or physically impaired in moving about their dwelling. For example, a person who is temporarily disabled by virtue of surgery or an accident, or one whose muscles have weakened during a period of long recovery from illness, may find it possible to move about with mechanical assistance. Mechanical locomotion assisting devices are beneficial to persons who have permanently lost the use of one or more bodily members, including those patients who use prosthetic devices. Extremely obese individuals who are unable to support their weight independently can also benefit from mechanical assistance.
Many such people who are partially ambulatory generally prefer to avoid wheelchairs. In order to maintain or regain leg muscle tone and strength, they must continue to exercise their legs by standing or walking. However, they must have help to rise up from a chair or bed to a standing position and usually must be supported to walk. For purposes of simplicity and clarity, all such individuals are collectively designated herein as the "patient", although many are not institutional "patients" in the strict sense of the word.
In an institutional setting, such as a nursing facility or hospital, partially ambulatory patients must await the assistance of busy aides or nurses to rise and move about. As a result, the patient often experiences inconvenient delays, or may be too rushed to enjoy meaningful leisure or privacy in moving about. Heavy or large patients typically experience increased difficulty and inconvenience, since more than one staff member may be required to safely lift the patient and support him for walking. Nursing home care usually does not facilitate proper exercise.
Partially ambulatory patients who care for themselves may use lifters, canes, or similar support devices to assist them to rise and move about. Various such support devices have been proposed in the prior art known to me. For example, U.S. Pat. No. 3,553,746, issued to Seiger on Jan. 12, 1971, discloses a rigid, generally T-shaped framework adapted to be positioned near a patient's bed or chair. The framework comprises an arm support to be grasped by the person to pull himself up from the bed without assistance. The structural aid proposed by O'Kennedy in U.S. Pat. 3,591,874 issued July 13, 1971 comprises an angular handlebar mounted upon a wheeled platform for supporting a disabled person. The patient grasps the handlebar of the scooter-like device and pulls himself up to a standing position.
However, such devices are impractical for the person who cannot at least temporarily support his full weight on one or both legs. Moreover, some individuals, and in particular those who are large or heavy, lack the necessary flexibility or strength in their arms and back to pull themselves up on a rigid support. Additionally, such devices are not suitable for use as a mobile support or walker, so the patient must subsequently support himself on furniture, walls, or other apparatus in order to move about without assistance. Some mechanical systems suffer from the disadvantage that they cannot "clear" the patients bed properly to readily enable him to stand.
Numerous types of mobile supports or "walkers" are also known in the prior art. King, Pat. No. 4,510,956 issued Apr. 16, 1985 illustrates a wheeled, generally U-shaped framework which surrounds the body of the patient. The patient leans his Weight on cushioned arm supports on either side of the framework and pushes himself forward. Braking spurs may be selectively engaged by manipulation of a hand-operated brake bar associated with the front of the frame. A powered support disclosed by Houston et al., U.S. Pat. No. 4,802,542 issued Feb. 7, 1989 comprises a frame while permits the disabled individuals to move about in a generally upright position. The patient using the Houston et al. device generally does not walk on his own power but is propelled about, much as in a wheelchair, except that the patient is standing.
Such prior art walkers generally do not provide adequate means for assisting the patient from a seated to a raised position. Those who do not have sufficient strength in their arms to support their body weight must have assistance to mount and dismount the walker. Moreover, typical prior art walkers do not provide any power-assist lift means. It is desired to provide an automated device which may be employed to assist a patient to rise from a seated to a standing position and to ambulate comfortably without assistance from others.
U.S. Pat. Pat. No. 3,596,298 issued to Durst, Jr. on Aug. 3, 1971 comprises a wheeled frame adapted to lift the patient from a seated to a standing position. A pair of support stanchions extend vertically upwardly from the wheeled frame and support a body-receptive cage. The body cage includes cushioned arm rests and a cushioned back rest against which the patient may lean. Hydraulic cylinders dynamically couple the stanchions to the frame, and may be activated to move the stanchions and the body cage between the upright position in which the stanchions stand generally perpendicular to the frame to an reclined position, in which the stanchions extend at an angle of roughly forty degrees from the frame. Thus the patient is reclined to facilitate movement in or out of a chair.
Of somewhat more relevance to the instant invention is the motorized lifter/walker disclosed by Thomas, U.S. Pat. No. 3,999,228, issued Dec. 28, 1976. The latter device comprises a large wheeled framework adapted to support a pulley-driven patient hoist. The patient straps himself into a harness associated with the hoist and activates the motor by manipulating a hand control mounted on the frame. The motor drives the pulley, which supports the weight of the patient and gently pulls him to a standing position. Once the patient is standing, he can use the wheeled framework as a walker and move about virtually without assistance from another. This device greatly facilitates the patient's independent movement.
However, there are various disadvantages associated with known prior art devices. Some devices are difficult to balance. Many devices must be adapted to use in restricted-space areas, and passage through residential hallways or doors is often difficult. Some devices cause the patient to suffer considerable discomfort in his back and chest as if they are hoisted vertically upwardly from the torso. Many devices are too cumbersome or too large to adequately clear a mattress or slide under the bed. Many devices lack adequate support structure to permit the patient to walk forward without the assistance of another person.
Thus it is desired to provide a safe, automated lift-assist device which may be comfortably and conveniently used by a wide variety of patients who are partially ambulatory for moving about independent of assistance from others. It is also desired to provide a machine which permits the patient to rise and walk without depending upon another person for help.